Problem $5\mathrm{.}33$ Compute the design moment strength, $M_n,$ of

the beam shown. How much can this permissible moment be

increased if $3$#$9$ bars are added to the top $2\frac{1}{2}$ in$.$ from the

compression face, $f_c^{\text{'}}=4000,$ and $f_y=60,000?$

$($Ans$.740\mathrm{.}5ft-k,36\mathrm{.}5ft-k)$